Spatial domain directional intra prediction has been shown to be very effective to remove the correlation between the pixels in the current block and reconstructed neighbors. In AVC, 8 directional prediction modes (plus the DC prediction mode) are defined. The prediction mode number is signaled to the decoder using a simple predictive coding method. The basic intra prediction has two major disadvantages: 1) the small number of directions does not provide sufficient precision to cover arbitrary directional patterns; and 2) the mode number prediction from neighbors is not accurate enough to exploit the geometric dependency between blocks. Increasing the number of directions typically results in a lower residual energy; however, the cost for signaling the prediction mode is able to also increase significantly such that the little gain is observed. This is particularly the case for small block sizes such as 4×4 or 8×8.